A four-wheeled utility vehicle traveling off-road is typically a four-wheel-drive vehicle and is equipped with an engine unit mounted to a vehicle body frame thereof, a passenger seat in the vicinity of a center of a vehicle body thereof, and a load-carrying platform at a rear region of the vehicle body (see Japanese Laid-Open Patent Application Publication No. Sho. 63-20284). To be specific, the passenger seat is placed on seat support frame members provided on the vehicle body to extend substantially vertically upward from right and left sides of a main frame member forming a floor at a center section of the vehicle body, and a rear frame member is mounted behind the passenger seats to support the load-carrying platform. The engine unit is disposed in a lower space surrounded by the seat support frame members and the rear frame member. The engine unit includes a belt-drive continuously variable transmission (CVT) such as a belt converter on a side surface of the engine body.
When the engine unit of the four-wheeled utility vehicle is maintained, an operator cannot easily access the engine unit because the engine unit is surrounded by the frame members. So, the operator cannot easily maintain the engine unit. Especially when a belt of the belt-drive CVT is changed, it is necessary to remove a cover of the belt-drive CVT from the side of the vehicle body. In this case, the cover cannot be removed because the cover will be interfered with by the frame members surrounding the engine unit. In this situation, maintenance operation of the engine unit must be carried out after the engine unit has been taken out from the vehicle body.